Method of connecting elements of punching units



G. F. WALES 2,361,668 METHOD OF CONNECTING ELEMENTS OF PUNCHING UNITS Oct. 31, 1944.

2 Sheet s-Sheet 1 Original F ile d Feb. 17, 1941 m" INVENTOR BY C W ATTORNEYS v Patented et. 31, 19 r METHQI) (19F ELEMENTS i1?! UNJI'ES George F. Wales, Kenmore, N. Y.

Griginai application February 17, 1941, Serial No. 379,185. Divided and this application Deccan her 1, 194i, Serial No. 421,167

2 Claims. (Cl. 29-148) This invention relates to a method of asing a modified form of the stripper means of sembling some of the elements of a sheet matewhich parts are connected by a method of this rial punching apparatus and more particularly invention, which form differs slightly from that to a method for connecting the cylindrical body shown in Fig. 1. and ring-shaped head of a punch and a method In the following description similar characters for assembling the. elements of a stripping device of reference indicate like parts in the several used in connection with the punch of a sheet figures of the drawings. material punching unit. The punching unit which embodies parts made This application is a division of an application in accordance with the present invention include for Letters Patent of the United States, filed a holder having a lower base or shoe III which by myself February 17, 1941, and serially numis provided on its upper side with a die seat ll bered 379,185, patented January 6, 1942, No. and a slug chute l2 and an upper horn or head 2,268,787. l3 which is separated from the base by a gap The punching units of this character, as herel4 and provided above the die seat with a vertofore constructed, included a punch body havtical guide opening l5. The holder is supported ing a head which was either formed integrally by a templet plate l6 which rests on the bed 9 at the upper end thereof or the head was made of the press and is secured to the underside separate from the punch body and secured to the of the holder by a screw I1 and held against upper end of the punch body by riveting, screwturning horizontally thereon by a locating screw ing or similar method and the stripper sleeve I8 engag wi an Op N in e p et which: received the punch body and the collar plate. Above the holder is arranged a vertically on this sleeve which was engaged by the lower movable ram 20. The seat I l receives aperforatend of the stripper spring were connected by a ing die 2| provided with a die opening 22 which screw joint or the like, both of which methods receives the slug removed from the sheet mateare unsatisfactory on account of the cost and 25 rial workpiece 23, such as sheet metal, and dealso on account of the parts becoming either loose livers the same to the discharge chute I 2. or detached and therefore involve loss of time The punching unit which is shown in Figs. 1, inkeeping the apparatusinworking condition. 2 and 3 and which cooperates with the die It is the object of this invention to provide tor perforating the workpiece and strip the. an improved method for securing a head to the latter from the punching unit is constructed as upper end of a punch body and also an improved follows:

method for securing a collar to the stripper The numeral 24 represents the vertical body sleeve of the punching unit whereby these conof the punch, the lower end of which forms a nections can be made more economical and cutting bit 25 cooperating with the upper edge rendered more reliable in operation. of the punching opening 22 in the die 2| for The accompanying drawings represent the removing a slug from the workpiece during the punching apparatus of which certain elements operation of forming a hole in this workpiece. constitute the products of the improved methods At its upper end the punch body is provided with forming the subject of this invention and these 40 a head 26 which, together with the punch body, drawings also illustrate the apparatus whereby are adapted to be engaged by the ram 20 and these products are made in accordance with moved downwardly thereby causing the bit to these methods. perforate the workpiece.

In these drawings: The punch body and head are both preferably Fig. 1 is a sectional side elevation of a sheet 4.5 of circular or cylindrical form in cross section metal perforating apparatus embodying one and connected with each other by the following 7 form of parts made in accordance with the means and method:

methods of this invention. Adjacent to its upper end the body of the Fig. 2 is a top plan view of the same. punch is provided on its. periphery with one or Fig. 3 is a fragmentary horizontal section, more annular grooves or recesses 21, for extaken on line 3-3, Fig. 1. ample, two grooves as shown in Figs. 1 and 4.

Fig. 4 is a vertical section showing the method The grooved part of this body is arranged within of securing the head to the body of the punch a central opening 28 in the punch head and in accordance with this invention. 1 metal from the bore of the opening in the head Figs. 5, 6 and 7 are vertical sections showing is displaced inwardly into these grooves so as to various stages in the use of the method and apform annular coupling ribs or keys 29 which paratus for securing the lower spring supportinterlock the punch body and head and render ingcollar of the stripping device to the punch the same practically integral and, inseparable. guide sleeve in accordance with this invention. The union of the punch body ,and head in this Fig. 8 .is a fragmentary vertical section showmanner may be effected, as shown in Fig. 4, by

placing the punch body downwardly in the socket 38 of an upright holder 3| so that the bit is spaced from the bottom of this socket and the upper end of the body projects above this holder, then placing the ring-shaped punch head 26 upon the holder 3| so that the opening or bore in the head receives the punch body and the upper sides of the punch body and head are flush, and then subjecting the metal of the head immediately around the-bore thereof to a squeezing or swaging operation by means of an annular swaging bead 32 arranged on the upper side of the holder 3| and engaging the underside of the punch head concentrically with its axis and an annular swaging head 33 arranged on the underside of a former 34 and engaging the upper side of the punch head concentrically with its axis. Upon moving the holder 3| and former 34 toward each other between the bed 35 and the ram 36 of a press, the lower and upper swaging beads 32, 33 displace a part of the metal of the head inwardly from the bore of the same into engagement with the grooves or recesses 21 of the punch body and thus securely interlock and connect the same.

During this operation the punch body and punch head move downwardly relative to the holder 3| an extent correspondin to the amount of metal displaced to form the interlocking or coupling beads 29. When the punch body fits fairly snug in the socket 30 of the holder 3| this body will be held therein by friction preparatory to forming the ribs or keys 29 but permit this body to slide downwardly while the head 26 moves downwardly during the operation of swaging the ribs or keys 29 from the head into the grooves 21 of the body. If desired the position of the holder 3|, forming die 34, punch body 24 and punch head 26 maybe reversed between the bed 35 and ram 36 particularly when the punch body fits loosely in the holder and punch head.

The numeral 31 represents a guide sleeve or tube which is arranged centrally within the guide opening of the punch mechanism holder and in which the body of the punch slides vertically. The upper part of the guide sleeve is arranged within an upper collar or guide ring38 which slides vertically within the upper partof the holder guide opening |5. The upper end of the upper collar engages with the underside of the punch head 26 and its lower end is free to slide downwardly on the guide sleeve an undetermined extent but the extent of upward movement of the upper collar relative to the guide sleeve is limited by a downwardly facing annular stop facing annular shoulder 43 and within the lower part of its bore with an annular temporary rib or bead 44, as shown in Fig. 5. The bore of the lower collar has its lower part enlarged so as to form a downwardly facing annular shoulder 45 within this collar. The guide sleeve, upper and lower collars and the spring together form elements of the means whereby the sheet of metal and the punch are separated or stripped from one another after the operation of a hole in the sheet of metal has been completed. Preparatory to permanently assembling these stripping elements the same are first stacked loosely in a vertical column by placing the lower collar on a support, block or anvil 46 which rests on the bed 41 of a press and provided with a vertical opening 48 in line with the bore of the lower collar 4|, as shown in Fig. 5, then placing the spring 42 while in a shoulder 39 formed on the upper part of the periphery of the guide sleeve and an upward facing annular shoulder 40 arranged internally on the lower part of the upper collar and engaging the shoulder 39 of the guide sleeve.

The numeral 4| represents a collar secured to the periphery of the guide sleeve at the lower end thereof.. Between the upper and lower collars 38 and 4| a stripper spring 42 of helical form surrounds the guide sleeve and bears at its upper and lower ends against the upper and lower collars 38, 4| respectively, and is preferably under an initial tension when the upper and lower collars are spaced apart their fullest extent.

To produce a permanent connection between the guide sleeve and the lower collar the same are connected in the following method by the means shown in Figs, 5, 6 and '7:

Initially the guide sleeve is provided on the lover part of its periphery with a downwardly wholly expanded or relaxed condition with its lower end in engagement with the top of the lower collar, then placing the upper collar 38 with its underside in engagement with the upper end of the spring, and then inserting the guide sleeve 31 downwardly through the upper collar and the spring until the shoulder 39 of the guide sleeve engages with the shoulder 40 of the collar, at which time the lower end of the guide sleeve projects partway into the upper small part of the bore of the lower collar and the lower external shoulder 43 is spaced upwardly from the upper side of the lower collar, as shown in Fig. 5. After the stripper elements have been thus loosely stacked they are subjected to a further operation for completing the assembling of the same suitable for use in connection with the punch and die of the sheet metal perforating apparatus. For such completion of the stripper unit a swaging or expanding rod, wedge or tool is employed which has a large round upper part 49 of a diameter corresponding to the bore of the upper part of the guide sleeve 31, a lower round part 50 of a diameter equal to the bore of the rib or head 44 and the reduced lower part 5| of the opening in the supporting block 41, and a central downwardly tapering conical part 52 arranged between the large upper part 49 and the small lower part 58 of the swaging tool. This tool is passed with its reduced part lowermost through the stack of loosely assembled stripper elements until its lower small end engages the small part 5| of the guide opening in the supporting block and the large upper part of the tool engages with the bore of the guide sleeve and the small lower end of the conical part 52 of the tool reaches the bore of the temporary bead 44in the guide sleeve. Upon now moving the swaging, or expanding tool downwardly another step by means of the ram 53 of a press, or otherwise, while the supporting block 46 rests on the bed or table 41 of a press, the tapering part 52 of this tool, by engaging with the internal head or rib 44 of the guide sleeve, will move the latter downwardly until the shoulder 43 of the sleeve engages the upper side of the lower collar 4|, as shown in Fig. 6, and place the spring 42 under an initial compression. Thereafter a continued downward movement of the swaging tool independently of the sleeve and the other elements of the stripper mechanism will cause the tapering part 52 of thetool to displace or swage the bead 44 outwardly so that the same d sappears from the bore of the guide sleeve and leaves this bore even or of uniform diameter throughout its length and at the same time the peripheral part of the guide sleeve transversely in line with the bead will be swaged or displaced outwardly so as to form an external annular head or rib 54 on the guide sleeve which enters the enlarged lower part of the bore of the lower collar 4| and en-' gageswith the downwardly facing shoulder 45, as shown in Fig. 7, thereby locking the lower collar 4| between the lower shoulder 43 and the external bead 54 of the guide sleeve and connecting the same so that the same are firmly united and incapable of being separated by ordinary means.

In the construction shown in Figs. "'1 and 2, a guide button for the front end of the punch is employed which has a, guide disk 5 bearing with its upper side against the lower end of the guide sleeve 31 and its lower collar 4| and adapted to rest with its underside on top of the sheet of metal or workpiece which is to be perforatedl At its central part this guide disk is provided with a guide opening 56 which receives the bit 26 or lower cutting end of the punch body and positively guides the same in its movement toward and from the workpiece. At its periphery this guide disk is provided with an upwardly projecting annular guide flange 51 which surrounds the periphery of the lower stripper collar 4| and slides with its peripheral surface on the bore of 25 the guide opening I5 in the horn of the punch holder. In this construction the lower stripper, collar 4| is spaced from the bore of the guide opening l5 in the punch holder and the guide butten 55, 51 therefore performs the whole function of guiding the lowermost end of the punch bit on the holder and maintaining the bit in accurate alinement with the cutting edge of the slug opening in the die.

When no workpiece is present between the punch guide button and the die, the punching unit merely floats in the guide opening l5 of the unit and drops by gravity so that the punch guide button rests on the die button. Upon now pushing a workpiece between the die and punch 4 guide button, which can be done due to the chamfered, bevelled or cam edge 58 on the die and the chamfered, rounded or cam edge 59 on the punch guide button, the latter together with the opening IS in the horn of the punch holder and the upwardly projecting annular flange 62 of the punch guide button also engages the bore of the guide opening I5 of the holder horn but only 5 surrounds the reduced lower part 53 of the lower ensure a firm and reliable connection between the respective members and prevents separation of the same under the severest service, thereby eliminating repairs and avoiding interruption in the use of the punching apparatus of which they form elements.

I claim as my invention:

1. The hereindescribed method of assembling the elements of a stripping device for use in con? nection with a sheet material punching unit which stripping device includes a guide sleeve provided at its upper end with an external downwardly facing shoulder and at its lower end with an external downwardly facing shoulder, an upper collar slidable on the upper part of said sleeve and provided with an upwardly facing internal shoulder engaging the upper shoulder of said sleeve, a lower collar arranged on the lower end of said sleeve and engaging its upper side with the lower shoulder of said sleeve and having an 0 internal downwardly facing shoulder and the lower part of said sleeve being expanded into engagement with the downwardly facing shoulder of said lower collar, and a spring interposed between said collars, said method including the provision of an internal annular rib within the lower part of said sleeve, loosely assembling the several members in a vertical stack with the spring relaxed and the lower end of the sleeve partly inserted in the lower collar and the lower shoulo der of the sleevespaced from the top of the lower collar, and then forcing a swage tool having a surface tapering downwardly in said sleeve and during the first part of this movement causing the tapering surface of this tool by engaging with punch and stripper elements will be lifted by the '45 the internal rib of the sleeve to lower the latter wedge action of the chamfered edges 58, 59 when engaged by the edge of the workpiece. During the subsequent descent of the ram 20 the same upon engaging the head and body of the punch will cause the lower cutting or bit end of the punch body to move downwardly in the punch guide button and into engagement with the workpiece and out out a slug from the latter so as to form a hole therein, which slug is discharged through the central opening in the die and the delivery chute in the base of the holder. As the body and headof the punch descend this head by engaging the top of the upper collar 38 also depresses the latter and compresses the stripper spring" a greater extent and when the pressure of the ram is removed from the top of the head and body of the punch the resilience of the spring 42 lifts the upper collar 38 and also the punch supported thereon and strips the bit of the latter from the '1 hole which has been'formed in "the workpiece.

Instead of utilizing the punch guide button as the sole means of guiding thebit of the punch in the guide opening 150! the punch and die holder, as shown in Fig. 1, this guiding effect may be make the bore of the sleeve of uniform diameter d and also displace material on the adjacent part of the periphery of this sleeve transversely in line with said rib outwardly into engagement with the internal shoulder of said lower collar, and thereby interlocking said sleeve and collar and causing said spring to'be held in a compressed condition.

2. The herein described method of assembling elements of a punching unit which includes a guide'sleeve, a lower collar fixed on said sleeve, an upper collar slidable on said sleeve but limited in its upward movement thereon and a spring mounted under compression between said collars;

said method comprising forming said sleeve with a deformable securing shoulder, loosely assembling said sleeve, collars. and spring, thenapplying pressure to the shoulder for forcing said sleeve and upper collar downwardly into required position relative to the lower collar and placing said divided between the lower collar of the stripper 7o spring under. an initial compression and then conmechanism and the punch guide button; as shown in Fig. 8. As there shown the lower collar of..

the punch guide sleeve 31 has its upper part of suftlciently large diameter that the periphery 6| of the same ngages with theboroof the guide 15 lowercollar GEORGE F. WALES. 

